As shown in FIG. 18, in a conventional acceleration sensor, a sensor main body 101 is sealed by a ceramic package 103 and a lid 105. In such a conventional acceleration sensor, there has a problem that the application of an expensive ceramic package results in high costs. In addition, there has a problem that the application of a ceramic package also causes the sensor to become bulky and heavier.
Moreover, as shown in FIG. 19, a wiring pattern 109 is provided on a substrate 107 of the sensor main body 101. The wiring pattern 109 is selectively formed on a flat surface of an oxide film 113 provided on the substrate main body 111. A nitride film 115 is formed in a manner so as to cover the surface of the oxide film 113 and the wiring pattern 109. Since the film thickness of this nitride film 115 is set to almost constant value, the surface of the substrate 107 is in an irregular state due to the presence of the wiring pattern 109.